The video tutorial introduces the concept of light, explaining its importance for visibility. It distinguishes between natural sources like the sun and stars, and artificial sources like electric lamps and candles. The tutorial further explains luminous objects, which emit their own light, and non-luminous objects, which do not. Examples include the sun and electric bulbs as luminous, and humans and tables as non-luminous. The moon, despite appearing bright, is non-luminous as it reflects sunlight. The tutorial concludes by summarizing these concepts.

What is the primary source of natural light during the day?

• Candle flames

• The moon

• Electric lamps

• The sun

Why do we need additional sources of light besides the sun and stars?

• Because natural light is not always available

• To save energy

• To make the night longer

• To reduce pollution

Which of the following is a controllable source of light?

• Glow worm

• The sun

• Stars

• Electric bulb

What is a luminous object?

• An object that reflects light

• An object that emits its own light

• An object that blocks light

• An object that absorbs light

Which of these is an example of a natural luminous object?

• Candle

• Table

• Electric bulb

• Sun

What are non-luminous objects?

• Objects that do not emit their own light

• Objects that reflect light

• Objects that absorb light

• Objects that emit light

Why is the moon considered a non-luminous object?

• It emits its own light

• It is a source of artificial light

• It reflects sunlight

• It absorbs light

Which of the following is NOT a luminous object?

• Table

• Glow worm

• Candle

• Electric bulb

How does a table become visible to us?

• It emits its own light

• It reflects light from a luminous object

• It absorbs light

• It is a source of natural light